This invention relates generally to the field of collapsible reusable shipping containers, and more particularly to an improved type of such container and a novel method of using the same for the shipment of hazardous or potentially hazardous materials in concentrated condition to a user.
It is known in the art to provide collapsible containers for the shipment of liquid of particulate materials to a user who uses the container in erected condition as a storage facility while progressively emptying the same. The container is subsequently collapsed for return shipment to the sender for reuse. Such containers are most conveniently made of fibrous materials such as multiply corrugated board and are configured to form a generally rectangularly shaped well at a lower end thereof for the storage of collapsed parts of the container, the well being closed by placing the cover of the container thereon.
Fibrous containers can also be equipped to ship materials in liquid form by providing a collapsible synthetic resinous bag having an inlet at the upper end thereof and an outlet at the lower end thereof. In some cases, a fibrous insert liner element is provided to prevent bulging of the container after loading.
Many such materials shipped in liquid form ar relatively dilute solutions of materials containing water or other readily available diluents or solvents. The cost of shipping the water content is relatively high, and in many cases, the contents which are relatively safe from an ecological standpoint, when in concentrated form, become hazardous only when activated by the solvent.
This problem can be avoided to a degree by the shipping of the concentrate in the absence of the solvent. The problem arises in that large quantities of liquid concentrates are often inherently dangerous, and thus require steel drums for shipment, which are costly to use, and must be thoroughly cleaned to environmental standards before return, a costly process which makes their use all but prohibitive. In the case of particulate concentrates shipped in large quantities, smaller amounts must be individually mixed for use and stored in non-disposable storage facilities. These facilities must also be thoroughly cleaned at frequent intervals to the same standards, again, a relatively expensive inconvenience.